Pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA) syndrome

This is an extremely rare autosomal dominant syndrome. It is caused by mutations in a gene called the PTSTPIP gene, which lead to production of an abnormal protein. The abnormal protein leads to overactive inflammation through mechanisms which are not yet understood. Attacks may appear after minor trauma and symptoms include:

  • a deep scarring rash, known as pyoderma gangrenosum
  • joint pain and swelling, that looks like a joint infection
  • severe acne

As in all the inherited fever syndromes there are raised levels of inflammatory markers.

Treatment with injected drugs, such as anakinra, that block certain inflammatory proteins (cytokines) may be effective. Anakinra has to be given at home every day. Another drug of this type, etanercept, may also be helpful.

The side effects of these drugs include:

  • stinging
  • skin redness at the injection site, in some people
  • increased risk of infection.

In general the infections reported have been mild but all patients should be screened for tuberculosis and asked about a history of other infections before starting such drugs.